Passive louver-based daylighting system

Abstract

A daylighting system for use in a building including a louver array having a first longitudinal element, and a second longitudinal element spaced therefrom. At least one of the first and second elements has an asymmetrical profile, each of the first and second longitudinal elements has a bottom profile including a parabolic surface, portions of opposing surfaces of the first and second longitudinal elements define a compound parabolic concentrator profile having a non-horizontal centerline that is tilted upwards, and the array prevents line of sight therethrough. A louver for a daylighting system includes (i) a leading edge defined by a leading connecting surface disposal between a parabolic concentrator surface and a flat surface; and (ii) a trailing edge defined by a trailing connecting surface disposed between a lower compound parabolic concentrator profile, and an upper compound parabolic concentrator profile. A method for designing a louver profile is provided.

What is claimed is: 
     
       1. A louver for a daylighting system comprising:
 a leading edge defined by an intersection of:
 a parabolic concentrator surface, and 
 a flat surface; and 
 
 a trailing edge defined by an intersection of:
 a lower compound parabolic concentrator profile, and 
 an upper compound parabolic concentrator profile. 
 
 
     
     
       2. The louver of  claim 1 , wherein the leading edge is further defined by a leading connecting surface disposed between the parabolic concentrator surface and the flat surface. 
     
     
       3. The louver of  claim 1 , wherein the trailing edge is further defined by a trailing connecting surface disposed between the lower compound parabolic concentrator profile and the upper compound parabolic concentrator profile. 
     
     
       4. The louver of  claim 1 , wherein the parabolic concentrator surface, flat surface, lower compound parabolic concentrator profile, and upper compound parabolic concentrator profile define an asymmetric profile. 
     
     
       5. The louver of  claim 4 , wherein the asymmetric profile comprises a generally triangular profile. 
     
     
       6. The louver of  claim 5 , further comprising an apex disposed between the leading edge and the trailing edge. 
     
     
       7. The louver of  claim 6 , wherein the apex is disposed in a downward direction from the leading and trailing edges. 
     
     
       8. The louver of  claim 6 , wherein an upper surface formed between the leading edge and the trailing edge comprises a discontinuous contour. 
     
     
       9. The louver of  claim 8 , wherein the discontinuous contour comprises a pair of arcuate surfaces meeting at a boundary line. 
     
     
       10. The louver of  claim 6 , wherein an inlet surface formed between the leading edge and the apex comprises the flat surface. 
     
     
       11. The louver of  claim 6 , wherein an outlet surface formed between the apex and the trailing edge comprises the lower compound parabolic concentrator profile. 
     
     
       12. The louver of  claim 1 , wherein at least one of the parabolic concentrator surface, flat surface, lower compound parabolic concentrator profile, and upper compound parabolic concentrator profile comprises a reflective surface. 
     
     
       13. The louver of  claim 12 , wherein the reflective surface is at least partially specular. 
     
     
       14. The louver of  claim 12 , wherein the reflective surface is formed by at least one of a deposition process, a reflective film coating, or a polishing step. 
     
     
       15. The louver of  claim 1 , wherein a profile defined by the parabolic concentrator surface, flat surface, lower compound parabolic concentrator profile, and upper compound parabolic concentrator profile is defined by at least one of extrusion and molding. 
     
     
       16. The louver of  claim 1 , wherein an angle of the flat surface with respect to horizontal is about 45°. 
     
     
       17. A louver for a daylighting system comprising,
 a leading edge defined by an intersection of:
 a parabolic concentrator surface, and 
 a flat surface; 
 
 a trailing edge defined by an intersection of:
 a lower compound parabolic concentrator profile, and 
 an upper compound parabolic concentrator profile; and 
 
 an apex disposed between the leading edge and the trailing edge, in a downward direction from the leading and trailing edges, 
 wherein (i) the parabolic concentrator surface, flat surface, lower compound parabolic concentrator profile, and upper compound parabolic concentrator profile define an asymmetric profile comprising a generally triangular profile and (ii) a height measured between the leading edge and the apex is selected from a range of about 0.5 inches to about 2.0 inches. 
 
     
     
       18. A louver for a daylighting system comprising:
 a leading edge defined by an intersection of:
 a parabolic concentrator surface, and 
 a flat surface; and 
 
 a trailing edge defined by an intersection of:
 a lower compound parabolic concentrator profile, and 
 an upper compound parabolic concentrator profile 
 
 
       wherein at least one of the parabolic concentrator surface, flat surface, lower compound parabolic concentrator profile, and upper compound parabolic concentrator profile comprises a reflective surface, and a minimum reflectance of the reflective surface is selected from the group consisting of 50% reflectance, 92% reflectance, 95% reflectance, and 98% reflectance. 
     
     
       19. A louver for a daylighting system comprising:
 a leading edge defined by an intersection of:
 a parabolic concentrator surface, and 
 a flat surface; and 
 
 a trailing edge defined by an intersection of:
 a lower compound parabolic concentrator profile, and 
 an upper compound parabolic concentrator profile, 
 
 wherein a width between the leading edge and the trailing edge is selected form a range of about 1.0 inches and about 4.0 inches.